Add event sourcing slides

src/content/slides/event-sourcing.md

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+---
+title: Event sourcing
+pubDate: 2024-05-07
+draft: true
+---
+
+# Event sourcing
+
+---
+
+## Intent/Command
+
+### VS
+
+## Event
+
+---
+
+## Intent/Command
+
+- **Tense:** Actions are not yet taken (event names are in present form).
+- **Consumer:** Meant for a **specific** consumer
+- **Purpose:** Invoke behavior
+- **Immutability:** Intent can change
+- **Dependency:** Producer is aware of the consumer and the message definition is controlled by consumer
+
+<!-- .element: class="fragmented-list" -->
+
+---
+
+![Intent/command](/assets/event-sourcing/command.svg)
+
+### Command intended for a specific consumer
+
+---
+
+## Event
+
+- **Tense:** Actions has already taken (event names are in past form).
+- **Consumer:** Meant for any consumer
+- **Purpose:** Notify update
+- **Immutability:** Event cannot change
+- Producer is unaware of the consumers
+
+<!-- .element: class="fragmented-list" -->
+
+---
+
+![Event](/assets/event-sourcing/event.svg)
+
+### Event intended for any consumer
+
+---
+
+### In the world of DDD
+
+---
+
+![Intent/command partner](/assets/event-sourcing/command-partner.svg)
+
+#### The schema for the message is equally dominated by the consumer and the producer
+
+---
+
+![Event Conformist](/assets/event-sourcing/event-conformist.svg)
+
+#### The consumers need to conform to the schema provided by the producer
+
+---
+
+## Event sourcing
+
+- Events are immutable and can be stored using an append-only operation
+- Events are simple objects that describe an action including associated data
+- Ability to go back in time
+- Re-build the world
+- Multiple consumer consume at their own speed
+
+<!-- .element: class="fragmented-list" -->
+
+---
+
+![](https://microservices.io/i/storingevents.png)
+
+---
+
+## Reference
+
+- [Event-Driven Message Types and Messaging Patterns](https://alirezafarokhi.medium.com/event-driven-message-types-and-messaging-patterns-d72de0182741)
+- [Domain Driven Design](https://www.oreilly.com/library/view/what-is-domain-driven/9781492057802/ch04.html)